The casein protein comprises three fractions, α, β and γ, according to their electrophoretic mobility. Casein hydrolysate is the hydrolyzed form of casein which includes, among others, the active beta-casein-derived peptide. It has been established that casein hydrolysate plays a role in immune responses against microbial and viral infections.
For example, U.S. Pat. No. 3,764,670 describes the anti-bacterial activity of casein fragments (obtained by proteolytic activity) and discloses proteolytic casein digests possessing antimicrobial properties against microorganisms.
U.S. Pat. Nos. 5,506,209, 5,538,952 and 5,707,968, all to Mukerji et al., and 5,968,901 to Andersson, et al., describe the administration of only human beta-casein, recombinant human beta-casein, and hydrolysates of both, in a liquid enteral formula, for treating respiratory syncytial virus, otitis media, H. influenza and other infections in infants.
U.S. Pat. No. 5,330,975 describes the use of sialic-acid binding kappa-casein and kappa-casein peptides for the neutralization of bacterial endotoxins, such as cholera toxin.
U.S. Patent Application publication No. 2009/0305947 describe the use of casein peptides and in particular casein hydrolysate for the management of the reproductive cycle of livestock and farm animals. U.S. Patent Application publication No. 2009/0069218 describe the use of casein peptides and in particular casein hydrolysate as a method for decreasing the length of the dry period of a lactating livestock animal, for increasing its milk yield and milk hygiene after parturition and for improving the livestock welfare.